/*
 * Copyright 2010 Impetus Infotech.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.impetus.kundera.db;

import java.util.List;

import com.impetus.kundera.metadata.EntityMetadata;
import com.impetus.kundera.proxy.EnhancedEntity;

/**
 * Interface to define contract between @Entity and Cassandra data units.
 * 
 * @author animesh.kumar
 * @since 0.1
 */
public interface DataAccessor {

    /**
	 * Write an entity to Cassandra DB.
	 * 
	 * @param e
	 *            EnhancedEntity
	 * @param m
	 *            Metadata
	 * @throws Exception
	 *             the exception
	 */
    void write(EnhancedEntity e, EntityMetadata m) throws Exception;

    /**
	 * Read an entity of type clazz with primaryKey id from Cassandra DB.
	 * 
	 * @param <E>
	 *            Generic type of Entity
	 * @param clazz
	 *            Entity class
	 * @param m
	 *            Metadata
	 * @param id
	 *            Primary Key
	 * @return the entity or null if no such entity
	 * @throws Exception
	 *             the exception
	 */
    <E> E read(Class<E> clazz, EntityMetadata m, String id) throws Exception;

    /**
	 * Reads a list of entities of type clazz with primaryKeys ids from
	 * Cassandra DB.
	 * 
	 * @param <E>
	 *            Generic type of Entity
	 * @param clazz
	 *            Entity class
	 * @param m
	 *            Metadata
	 * @param ids
	 *            Primary Keys
	 * @return the list
	 * @throws Exception
	 *             the exception
	 */
    <E> List<E> read(Class<E> clazz, EntityMetadata m,  String... ids) throws Exception;

    /**
	 * Delete an entity from Cassandra DB.
	 * 
	 * @param e
	 *            EnhancedEntity
	 * @param m
	 *            Metadata
	 * @throws Exception
	 *             the exception
	 */
    void delete(EnhancedEntity e, EntityMetadata m) throws Exception;
}
